Opto-isolated RS-232 for Icom CI-V
First thing I should say, this is my 'design' and I offer no guarantee that it will work for you, be careful if you build one, do your own testing to be certain it's not going to blow up your laptop and or radio, cause a rift in space time and the instant destruction of the entire universe as we know it. OK, guff out of the way, the Opto Isolated CI-V Interface I mentioned earlier, And the schematic! It's rough, hand drawn and there have been a couple of changes to component values, mainly because I found a document that suggests the CI-V interface port on the radio shouldn't have to sink more than 2.5mA, so one resistor has been changed (the 680R on pin 2 of the right hand side opto is now 2K) and another removed completely (the pull up on pin 5 of the left hand side opto) to comply with that. If I short the CI-V line with my ammeter, I get this: 1.6 milliamps, I'm comfortable with that. Currently (yeah yeah) it works reliably as a serial loop...